1. Field of the Invention (Technical Field)
The invention relates to a sensor for identifying at least one particle by means of Raman-spectroscopy, comprising an optical trapping system for the at least one particle, including a laser-beam source, acting further as a Raman excitation source for the at least one particle, and a Raman-spectrometer for measuring the spectrally modified light scattered by the at least one particle and for identifying same.
2. Description of Related Art
The article “Identification of Single Bacterial Cells in Aqueous Solution Using Confocal Laser Tweezers Raman Spectroscopy” by C. Xie et al., published in Analytical Chemistry, 2005, vol. 77, no. 4390-4397 reports on a rapid method for reagentless identification and discrimination of single bacterial cells in aqueous solutions using a combination of laser tweezers and confocal Raman-spectroscopy. The optical trapping enables capturing of individual bacteria in an aqueous solution in the focus of the laser beam, and levitating the captured cell well off a cover plate, thus maximizing the excitation and collection of Raman scattering from the cell and minimizing the unwanted background from the cover plate and environment. Raman spectral patterns excited by a near-infrared laser beam provide intrinsic molecular information for reagentless analysis of the optically isolated bacterium.
Although according to the article a rapid identification of single bacterial cells in an aqueous solution is possible, the sensor set up used therefore was experimental and not suited for wide spread use at distributed places throughout the world at which monitoring for harmful particles is a continuous need. This may relate to outlets for drinking water but also specific applications in a hospital environment or elsewhere.
With the invention it is aimed to provide a sensor which is suitable for such wide spread and local use where no extensive laboratory equipment is available.
A sensor according to the preamble of claim 1 is further known from WO-A-2006/130728.